Air compressor



R. H; HILL AIR COMPRESSOR July 29, 1952 2 SHEETS-'SHW- Filed Dec. 22,1945 y w n lINVENTOR.

L., f. L M E July 29,v 1952 R. H. H|| 2,605,044

AIR COMPRESSOR Filed Dec. 22, 1945 2 Sl-{EETS-SHEET 2 I N V EN TOR.190.955 71K .//g L,

Patented July 29, 1952 UNITED. STATES xeri;1\.ifr f QFFIC Robert H. Hin.Fcri Wa f 'rpkiieim .oii'rank and y J Wayne, Ind.. a corporation ofIndiana g Aiiiiieiincnnember-22, i945, scriaio. 636,864

" Y rioiaims. (o1. 23o-472V This invention relatesV to a positivedisplacement air compressor. K l K' v The object of the invention is toproduce .a simple, compact air: compressor Whichwill oper'- ate quietlyand Yeiiiciently'r `at a relatively high compressor speed lto deliverVair with low pulsation, which compressor may be mounted Yon and directconnected to a Standard electric motor, to form a readily portable unit.

4 In'an illustrative embodiment `of myinvention,

a compressor crank Y'case 'is mountedv directly on the end of ,astandard electric motor, and the compressor head mounted onthat crankcase. A cylinder 'is formed inthe head, and a -pistonris reciprocatedtherein 4thi'foug'h a rod driven by an eccentric crank-on the shaft ofthe electric motor. The piston isgenerally T-s'haped'in verticalsection;k Vwithy the stern of the T ei'tending upwardly into a guide'bore iii-'the head-to guide the piston and'perm'itit to bemade-substantially skirtless. 1

Intake and discharge passages are formed in the head, communicating withthe cylinder through valves in the lcylinder head.- The valve elements.are iformed Aas light-weight disks, carried With their seats and valveYsprings in unitary assemblies pressed in suitable .bores inthecylinderhead.

The compressor desirably vreceives .air through a screened silencing.and .intake tube; .which is desirably positioned to vform a handlefor'transporting the compressor. An inner intake screen is desirablykept'moist-and the crank-*casemaintained under slight vacuum, by ventingthe crank case through a valvedpassage which'open's to the intakepassage outsidesuch -inner screen. The relatively high speed-cf thecompressor delivers air with minimum pulsation, but preferably I formanabsorptionlc-hamber in the com-Y pressor base, and deliver air therefromthrough a tting which also embodies anoverload relief valve and a manualrelief and clean-out valve.

While my compressorl Yis designed forA associa;V

tion with an electric motonland is yso shown v in the accompanyingdrawing,v it may be driven by other sources'of powr,as by substituting.-an internal'` combustion engine .for ythe electric-motor.

The .accompanying ldrawings,y illustrate my in- Vention.' In suchdrawing's ig.- Vlisan endelevation of Va compressor embodyingl my.invention; Fig..2' is a side elevationof the compressor shown innig.V 1,with 'the' .crank ca'sefhead'; and outlet fitting Shownin section;.Figfis la' horizontal setion thro'ugl'iV the head olftlieA compressoryne, Ind., assigner togy Pump Company, Fort Fig. v3, showing the Valveunits; and Fig. .5 is .an

' elevation of the connecting rod and eccentric,

withV the big end o'f the rod shown in section.

The compressor is shown in the drawings as associated with an electricmotor Il). The crank case VIl of the compressor is mounted directly onthe end of the motorv l0, andthe compressor head l2 is mounted on thecrank case Il.

An eccentric I5 is` mounted on the Shaft I6 of the motor i6,convenientlybyakey Il 'locked in the key Way of the shaft IE by'a setscrew I8. The big end ofthe connecting "rod 2U is mounted on theeccentric fpreferablyby needle bearings il, and is heid against axialmovementby 'counterweight disks .22 attached against -the's'l'des' of'the eccen'tr'icl as bylbolts" 23. The'sniallend ton by a sleevehearingaiiiia pistcnpint. `Desirabiy, the ypiston pineis locked to the'piston by a cross pin 2.1; y

The piston 4is icrrri'e'ci of a ,carrier ,25 and `a head 30. Ihevcar'erextends upwardly' .to for-in a hollow guide Vrod'Z'slidableinfa centralguide borel in the 'head 12. "The pistnY head '13.0 is mounted on thecarrier "25, desir'ablylbyllocldng it against a suitable shoulderv'v'ith a lock' nuti which is pinned inlocked position. HThe pistonrhead se is relatively shcrtwith its side wall's'cf sufiicieni length tofonte ring band and' some bearing surface .against the @cylinder ."35,but

with substantially no skirt. Vv'Ilieuse of tl'ieguide 28 fully preventspiston vvbble Without the .necessity for any extended skirt .on thepiston. This permits the Di'stnafnd 'cylinder'.tobe .Short so that thecylinder can conve''nie'ritly be formed in the head; andreduces theWeightof the Inoving parts to facilitate operationat the relatively highspeed `(for a coi'n'pressor)A .of a standard` electric-motorl. Y

An intake .passage-37 lis ioimedj-inV the-head,

and to receive oneendlofan intaketube#3532` The Y passagelisshouldered-so that a lter screen 39 may .be received betweentheshoulderand the u v Desiiably; the screen 39 is formador,tvvohlayersjoiwiremesh,

y with an intervening layero f-.ffelt .An additienal ier-iai.

screen Qn'iay .be .placedin .the openend 4of the tube 33,.andi`f`desiredthee3@ may Acontain Silemnngvv material, but I have foundY that'lthecompressor operate ""th remarkablequietness withoutthe neces.A,si-llene.ing @heavier @12de .ebefrl-isrsecured to 1the .motor |!J,.s.by.,a.b`racket 44,' sothattlfie tube may serve .a'handle 6r.transportingthe compressor.

Y'rheiritake passagearieas tcaipair, ci iiiieie,

valves. Each such valve is formed in an annular body 50, shaped toprovide a valve seat 5l. A light-weight disk-shaped valve element 52 isassociated with the valve seat 5l, and its displacement is desirablylimited by a raised central portion Yof a holder 54, which portion mayalso serve to center a valve spring 53 supported by the holder 54. Thevalves are formed as units, and are pressed into bores in the top wallof the cylinder 35.

The outlet valves 55, which are similarly pressed in place, are similarin construction to the inlet valves 50-54 and have similar diskvalve-elements 56, but may be of slightly smaller size. An outletpassage 51 leads from the outlet valves 55, and is connected to a pipe58.

The Valve disks 52 and 5B are of light weight and of low inertia.Preferably, they are of spring steel about six to eight thousandths(0.006 to 0.008) of an inch thick, to give adequate lightness withsufiicient strength for long service.

A vent passage 42, drilled in the crank case and head, leads from thecrank case to communication with the intake passage just outside thescreen 39. A seat for a valve in this vent passage 42 is formed in achamber 43 in the upper surface of the crank case, and a disk valve 4 ispositioned in the valve chamber 43 against the seat when the compressoris assembled. The I head 45 of a screw in the lower surface of the headI2 overlies the valve disk 44 to limit its displacement.

The valved crank-case vent maintains the case under slight vacuum andleads normally escaping oil vapor to the intake, to moisten the filterscreen 39. Such oil vapor also supplements the splash system oflubrication, especially when high pressure operation tends to dry thecylinder walls, for under those conditions oil-vapor escape tends toincrease, and this is delivered through the intake for top-cylinderlubrication.

The cylinder head is secured to the crankcase, as by stud bolts, in aplane below the cylinder 35. The cylinder 35 and the bore for the pistonguide 28 are thus formed in an integral head, for permanent alinement.This arrangement also serves to place the compression space within theintegral head, where adequate air cooling may be obtained by a singleset of iins carried by the head.

The compressor is carried by a base 68, preferably by mounting the motorI on a suitable bracket 6l on that base 6U. The base 68 is formed toprovide an absorbing chamber G5, to which the pipe 58 leading from theoutlet passage 51 of the compressor is connected.

The compressed air is delivered from the absorbing chamber 65 through anoutlet connection E of a fitting 10, which also houses an overloadrelief valve and a clean-out and manualrelief valve. The over-loadrelief valve is formed in a boss 13 on the fitting 10. It has a plunger12 spring-pressed inwardly to urge its bluntly tapered inner end againsta seat formed in the fitting 1G, to normally close a passage 14 which isin open communication with the absorbing chamber 65.

A clean out tube 15 leads from near the bottom wall 64 of the absorbingchamber 65 upwardly through the fitting 10 out of communication with thenormal air delivery passage, to a valve 16 which is normally held inclosed position by the spring 11. A head on the stem of the Valve 16 maybe manually depressed to open the valve 16 4 and release air through theclean-out tube 15 to a relief opening 18. Normal operation of the reliefvalve 16, as when starting the compressor, will automatically giveclean-out action to remove any accumulation of moisture and oilcondensation. A 1

My compressor may, be direct connected through the connection 66 to adevice requiring compressed air, such for instance as a spray gun, agrease gun, etc.

The design of my compressor, and the low weight of its moving parts,contribute to make it operate quietly and eiiiciently at high speed, asat the standard high speed of the electric motor i0, or even atsubstantially higher speed. Oil vapor unavoidably escaping from thecrank case is carried by the vent-passage to the intake and utilized tomoisten the filter and for top lubrication, especially when operation athigh pressures tends to reduce normal top-cylinder lubrication.

Air delivery is smooth and prompt, to provide air at high pressure, orin greater quantities at lower pressure, as its use may require.

I claim as my invention:

1. An air-compressor, comprising a motor having a frame and a powershaft, a compressor crank case mounted on said frame, an eccentric crankmounted on said shaft within said crankcase, a compressor head on saidcrank-case, a cylinder formed in said head, a piston in said cylinder, apiston rod connecting said piston to said eccentric crank, a flat basesupporting said motor and compressor, said base having spaced upper andlower walls joined at4 their edges to form a flat absorption chambersubstantially coextensive with the base, said discharge passage beingconnected in open communication with said absorption chamber, and an airdelivery fitting on said absorption chamber.

2. An air-compressor, comprising a motor having a frame and a powershaft, a compressor crank case mounted on said frame, an eccentric crankmounted on said shaft within said crankcase, a compressor headv on saidcrank-case, a cylinderformed in said head, a central guidebore in saidhead yat the end of said cylinder, a piston in said cylinder having aguide slidably received in said guide-bore, -a piston rod connectingsaid piston to said eccentric crank, a screen in said intake passage, avent passage leading from said crank case and discharging to said intakepassage outside said screen, and a check valve in said vent passageopening toward said intake passage, said crank case being closed savefor said vent passage: I y

3. An air-compressor, comprising a motor, a compressor includinga pistonand cylinder, an eccentric crank connected for op-eration at motor speedto reciprocate said piston through short strokes insaidV cylinder, a datVbase supporting said motor and compressor, -a flat absorption chamberformed in said base, means connecting vthe discharge from saidcompressor in open communication with said absorption chamber, and anair delivery fitting on said absorption chamber.

4. An air-compressor, comprising a motor having a frame and a powershaft, a compressor :crank case mounted on said frame, an eccentriccrankmounted o n said shaft Within said crankcase, a compressor head onsaid crank-case and having an intake passage, a cylinder'forrned inVsaid head, a piston in said cylinder,` a piston rod connecting saidpiston to said eccentric crank,

a' screen in said intake'passage, a vent passage leading from s-aidcrank case and discharging to s-aid intake passage outside said screen,and a check valve in said vent passage opening toward said intakepassage, said crank case being closed save for said vent pass-age.

5. An air-compressor, -comprising a crank case and a crank mounted forrotation therein, a compressor head on said crank case, a cylinderformed in said head, a piston connected to the crank for reciprocationin the cylinder, an intake passage formed in said head, a crank-casevent passage in said head extending from said intake passage through theface of the hea-d joint with said crank case, a -connecting vent passagein said crank case, .a valve chamber in said vent passages at saidjoint, and a check valve `in the valve chamber opening toward saidintake passage, said -crank-case being closed save for said valved ventpassage.

6. An air-compressor, comprising a crank-case, a shaft mounted `forrevolution therein, an eccentric sleeve mounted Ion sai-d shaft, acylinder supported on said crank-case, a piston therein, a connectingrod having its big end rotatably received on said eccentric sleeve,counterweigh-t disks secured on the ends of said eccentric sleeve andpreventing axial displacement of said connecting rod therefrom, said-connecting rod being connected -to reciprocate said piston, and valved1ntake and disch-arge passages to and from said cylinder.

7. An air compressor, comprising a crank case and a crank mounted forrotation therein, a compressor head on said crank-case and having anintake passage, a cylinder formed in said head, a piston in saidcylinder, a piston rod connecting said piston to said eccentric crank, ascreen in 6 said intake passage, la vent passage leading from saidcrank-case and discharging to said intake passage outside said screen,anda check valve in said ven-t passage opening vtoward said intakepas-sage, said crank case being closed save for said vent passage.

ROBERT H HILL.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTSn Number Name Date 527,787 Heath Oct. 23, 1894893,854 Lock-e et al July 21, 1908 1,137,877 Manly et a1. May 4, 19151,187,031 Black et a1 June 13, 1916 1,305,758 Warnock -June 3, 19191,376,359 Quigley Apr. 26, 1921 1,555,287 Howe Sept. 29, 1925 1,556,040Shvely Oct. 6, 1925 1,789,395 `Summers Jan. 20, 1931 1,820,732 DaveyAug. 25, 1931 1,844,416 Bacher et al. Feb. 9, 1932 1,872,805 PetersonAug. 23, 1932 2,109,718 Bayers Mar. 1, 1938 2,136,098 Browne Nov. 8,1938 2,136,339 Halleck Nov. 8, 1938 2,155,236 Newell Apr. 18, 19392,163,391 Aikman June 20, 1939 2,267,479 Sturm Dec. 23, 1941 2,336,240Gavin Dec. 7, 1943 FOREIGN PATENTS Number Country Date 869,859 France1941

